Yes, you can set a custom URL for donors to get redirected to after they've donated!
Step 1
Log into your Donorbox dashboard, and navigate to your Campaigns page.
Step 2
Click on the Campaign editor:
Step 3
Click on "Edit Form" and choose "Post-Donation":
Step 4
Toggle on the Redirection section, labeled "Redirect to a custom URL after donation". A text box will appear for you to add the URL that you want donors to be taken to after they've donated - as shown below.
Add the URL, and save the changes. Also, please consider that if you use this option, the "Thank you" message will not be displayed.